What are diffractive optical elements?
The diffractive optical elements (DOE) also known as a computer-generated hologram or diffractive optical lens, to achieve the functions they utilize the wave nature of light. On the face of the optical window, they are a microstructure pattern that has the capability of refracting the light in a predefined pattern. These microstructures are designed in such a way to get the desired delay in the phase of the wavelength. The material which is used may differ according to our requirements. Each DOE has its unique optical function on wavelength. The shape and split laser beam in an energy-efficient manner.
How diffractive optical elements are made?
They are made from a thin optical lens in which, there is some kind of patterns embedded on it to get a different kind of delay for a specific wavelength of light. Generally, laser beams are used for this purpose. Some are binary elements where occurs only two-phase delay while others are analog phase delays. Various factors involved in defining the diffractive optical elements are such as the material that is used which all have a different refractive index, as in optical instruments refractive play an important role and the other is surrounding environment and light beam fall on element after passing through environment.
Types of diffractive optical elements
According to their function, they are divided into three main types:
- Diffractive beam splitter: it splits the input beam into the desired number of an identical beam which all have the same characteristics and separation angle between them. The split beam can be arranged: in a 1-dimensional or 2-dimensional array pattern.
- Diffractive beam sharper: it is of two types, namely diffractive diffuser and top-hat diffractive beam shaper. They both generate a flat-top distribution of energy in the desired intensity in the workplace. Doughnut or ring shape is also available.
- Beam foci elements: unlike others, it manipulates laser beam at the propagation axis, which generates the elongated focus.
With the right knowledge and tools, anyone can form a superposition of these types and use them for their work. The advantages or one can say the reasons to use these elements are discussed further in the article. Study them before you directly start using them.
Advantage of using diffractive optical elements
There are various advantages of using diffractive optical elements in our system where we require splitting or shaping of light such as the Splitting capabilities or flexible shaping, Low maintenance and system robustness (they are passive components with electronic components), Perfect angular accuracy, Ease of integration (they can be fabricated or structured according to the manufacturer requirement). There are many more advantages of these elements in our day-to-day life for which one can use them.